Term: Spell Slot

Regardless of how many spells a spellcaster has in their Library or Repertoire, they can only cast their spells a limited amount of times per Long Rest equal to a certain amount of times a day. These times per day are counted in slots. These are Spell Slots.

Every Spellcaster class has a Caster level associated with it, which gives more powerful spell slots via progression.The Caster Levels term page has a full chart, for the sake of ease. A spell slot's’s rank indicates its overall power, and the kind of spell that will be produced if a spell is Heightened or modified. These ranks range from 0-10 and beyond, with spell slots numbering from 1-10.